In installations for the production of sanitary articles hammer mills are used to break up cellulose webs. The cellulose is used in suction pillows.
Instead of hammer mills, openers have been used in recent times where a roller surrounded by saw teeth such as is used in the textile industry opens the cellulose web.
The opener consists essentially of a presentation device to the opener roller and a housing. Air guidance is important at the opener roller in order to convey the fibers away. Air aspired from the environment flows along the roller.
This is more difficult than with hammer mills. The removed fibers are conveyed in the same air stream to the sanitary machine where they are either separated from the air stream to be placed in intermediary storage, or are formed into a suction pillow directly at a forming wheel.
On the circumference of a forming wheel are depressions at the bottom of which is a sieving surface. The air together with the fibers is pulled into the depression, the fibers are deposited in the depression and the air is again pulled through the sieving surfaces and reaches a filter. The installation and operating costs of a filter are considerable. The accumulation is mainly of short fibers and dust whose reintegration into the process is problematic.